URANS computations for an oscillatory non-isothermal triple-jet using the k-ε and second moment closure turbulence models

M. Nishimura, N. Kimura

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Low Reynolds number turbulence stress and heat flux equation models (LRSFM) have been developed to enhance predictive capabilities. A new method is proposed for providing the wall boundary condition for dissipation rate of turbulent kinetic energy, ε, to improve the model capability upon application of coarse meshes for practical use. The proposed method shows good agreement with accepted correlations and experimental data for flows with various Reynolds and Prandtl numbers including transitional regimes. Also, a mesh width about 5 times or larger than that used in existing models is applicable by using the present boundary condition. The present method thus enhanced computational efficiency in applying the complex turbulence model, LRSFM, to predictions of complicated flows. Unsteady Reynolds averaged Navier-Stokes (URANS) computations are conducted for an oscillatory non-isothermal quasi-planar triple-jet. Comparisons are made between an experiment and predictions with the LRSFM and the standard k-ε model. A water test facility with three vertical jets, the cold in between two hot jets, simulates temperature fluctuations anticipated at the outlet of a liquid metal fast reactor core. The LRSFM shows good agreement with the experiment, with respect to mean profiles and the oscillatory motion of the flow, while the k-ε model under-predicts the mixing due to the oscillation, such that a transverse mean temperature difference remains far downstream.

Original languageEnglish
Pages (from-to)1019-1044
Number of pages26
JournalInternational Journal for Numerical Methods in Fluids
Volume43
Issue number9
DOIs
Publication statusPublished - 2003 Nov 30
Externally publishedYes

Keywords

  • Liquid metal cooled fast reactor
  • Mixing of jets
  • Reynolds stress equation
  • Thermal striping
  • Transitional flow
  • Turbulent heat flux equation

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Mechanical Engineering
  • Computer Science Applications
  • Applied Mathematics

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